The National Prosecuting Authority has hit back at critics who accuse it of being used to settle political scores.

"To all cases that go to prosecution, evidence must exist and it must dictate that there are reasonable prospects of conducting a successful prosecution, should the matter go to court," said spokesman Tlali Tlali.

He dispelled the perception that businessman Charles Modise's arrest was political.

"What is even more absurd is the implied suggestion that the courts are a part of this agenda," Tlali said.

Modise was arrested shortly after publicly announcing that her had donated R500000 to the SACP which had not been properly accounted for.

Modise claimed to have given the money to then Cosatu president Willie Madisha. Madisha claimed to have given the money to SACP general secretary Blade Nzimande who denied any knowledge of the money.

"Modise was investigated by the Scorpions for charges that include fraud and money laundering. The investigation was authorised even before he could make public pronouncements about the R500000. The investigation around R500000 was not even conducted by the Scorpions," Tlali said.

He added the two matters remained two separate investigations by two separate agencies.

Modise is currently in custody after the Kimberley regional court refused him bail.

Modise's bail application is to be heard again tomorrow.

"All evidence the NPA presents in court can be put to scrutiny and all State witnesses may be put to cross-examination.

"There is no basis in law and in practice to exempt NPA evidence and/or witnesses from scrutiny and cross-examination," Tlali added.